Question: Simplify the following expression: $a = \dfrac{9}{4z} - \dfrac{1}{4z}$
Solution: Since the expressions have the same denominator we simply combine the numerators: $a = \dfrac{9 - (1)}{4z}$ Combine like terms: $a = \dfrac{8}{4z}$ Simplify by dividing numerator and denominator by 4: $a = \dfrac{2}{z}$